In a wide variety of applications and industries, there is a need to seal, connect, weld or otherwise manipulate tubes. For example, there is often a need to create a seal at a location along the length of a tube or a portion thereof. Such a seal may be desired to prevent or substantially reduce the flow of gaseous or liquid fluid between adjacent portions of a tube.
One example of an application in which a tube may be desired to be sealed is the sealing of tubes that contain blood or other bodily fluids. For example, blood may be drawn from a donor from flexible tubing that extends into a plastic blood collection bag. Once the bag is filled to its capacity, it may be desired to seal the tubing in order to prevent leakage and/or contamination or deterioration of the collected blood. After such collection, the blood may need to be typed and/or tested under various criteria. In order to provide a representative supply of blood for such typing and test purposes, a plurality of segments of the tubing may be sealed from one another to provide multiple sealed samples. Such samples may later be separately opened for typing and/or testing purposes.
Systems have been proposed to seal tubes using a pair of jaws such as electrodes for compressing tubing while applying radio frequency energy to melt the tubing and form a weld to effect a seal. Such systems generate a substantial quantity of radio frequency (RF) energy in order to heat and melt the plastic of the tubing sufficiently to form a weld. More specifically, a burst of RF energy may be transmitted across the jaws. The tubing represents a resistance to the RF energy transmitted therethrough and a capacitance between the jaws resulting in the development of heat to partially melt or soften the tubing and weld the opposing tubing surfaces to one another.
Radio frequency energy is considered to be electromagnetic energy at any frequency in the radio spectrum between 9 kHz and 3,000,000 MHz. Because of emissions or emanations from devices that generate RF energy, such devices should be constructed in accordance with good engineering design and manufacturing practice. It is also recognized that emanations from such devices should be suppressed as much as practicable. The United States has promulgated regulations to limit the level of emanations from such devices. Reference is made to Chapter 1 of Title 47 of the Code of Federal Regulations.
The foregoing comments apply not only to dielectric tube sealers but also to any apparatus configured to connect, weld, or otherwise manipulate tubes using radio frequency, heat, mechanical elements, or any other known means for manipulating tubes.